The Collaborative International Dictionary
Antozone
Antozone \Ant*o"zone\, n. [Pref. anti- + ozone.] (Chem.) A compound formerly supposed to be modification of oxygen, but now known to be hydrogen dioxide; -- so called because apparently antagonistic to ozone, converting it into ordinary oxygen.
Wiktionary
antozone
n. (context chemistry archaic English) hydrogen peroxide